Furnace



FURNACE March 'Filed- June 29, 1922 BBB BBB I 3751 Edgy, 8

Patented Mar. 15,11 922.

UNITED" STATES v 1,621,241 PATENT OFFICE.

WARREN c. DRAKE, or INWOOD, New 11031:.

FURNACE.

k plicationl filed 11111529, 1922. Serial a... 571,718.

This invention is an improvement in furnaces, and relates more particularly to, furnaces having progressive feed mechanisms or stokers, by which the fuel bed is caused to travel toward the discharge point or rear, the refuse, ashes or oli'nk'ers passing intoa pocket or receptacle, from the bottom of which the same is discharged in a regular or periodic manner. For example, the present invention may be used, and is shown, in connection with a boiler furnace having an underfeed stoker of a inclined type, and with an ash pocket at the rear from the bottom of which, the refuse is dischargedv downwardly. in a regulated manner, for. example b devices which reduce regulated manner under the control of the discharging or grinding device at the bottom. These difliculties include the overheat- .ing combustion, operating to ing of the. 'wallssurrounding the ash. pocket,- the burning away ofsuch walls, the attachment of hot'clinkers thereto and injury to thewalls from such clinkers. The present mventlon overcomes or mimmlzes' these .dlf

ficulties and increases 'eificiency byimprovurn anyunburnt -or partially burnt material passing through the ash pocket.

' .To the accomplishment ofthese' objects and advantages,-tlae present invention-consists in the novel furnace and the novel features of construction, ;combination, arrange 1 ent, operation a and detail herein described or illustrated. T

. In the accompapging drawings showing an illustrative emb unent of the present invention Figure 1 is a longitudinal section of a furnace containingmy improvements and Fi re 2 1s a sim lar partial sectlon on an arged scale.

The eiieral type 'of furnace, herein illu strated, is well known; and needs no detailed -description -beyond the following. The fuel bed, indicated by the line 8, rests beneath the combustion space 9 upon the various supporting surfaces to be described. At the front is shown wall '10 andat the opposite side or rear is the bridge wall 11, the combustion 'as the space to the rear of the extension and the discharge device s.

chamber being completed by two opposite side walls 12, which may be of any desired or well known construction. The fuel enters the furnace through the throat 13 beneath the front wall and passes progressively rearward over the grate 14 which is-shown as' part of an inclinedunderfeed stoker, althoughob-i viou'sly' the progressive action could be ob-' tamed by a chain grate or-otherwise. Be-

,yond the stoker or main grate is shown an extension grate 1 5, and. a continuation thereof 16 steeply inclined, below which is an approximately vertical apron or wall 17 constructed preferably of metal, but wholly or partially of refractory material if desired.

It will be understood that air is introduced where.

The'pocket 18 into which the refuse passes from the stoker proper, may be considered I grate 16 and apron plate 17, between these an upwardly inclined lower portion of the bridge wall 11, and laterally confined by the lower portions of the opposite side walls 12,

-withthe slowly operating discharge means at the bottom, sup ortingthe body of refuse, including ashes, inkers and perhaps some partially burnt or unburnt fuel, within the pocket. The bottom of the bridge wall may by forced draft into the fuel bed through the members of the main grate 14 and elsethe be provided with an extension or apron 19 closing the, space between 'the' bridge wall The discharge devices are shown as comare shown formed with tee'th21'arranged to operate as crushing elements so that large" cli'nkers passing'downwardly tothe ash pit 22 below would be reduced or ground to a prising one or more rotary bars,20 and these smaller size, with advantages well under-.

stood. a g 1 The grindingdevices 20 may be rotated in either direction, as they can operate against each' other or against the apron plates 17 and. 19, andthey are shown geared together by gears 23 external ,of thefurnace walls.

' The drive maybe continuous or intermittent,

.regula'ror irregular, for example 'by means of a pawl and ratchet 24 on one'of the rollers, the pawl carriedon an operating arm 25 arm 27 which in turn is rocked by a pitman 28 actuatedby a crank 29. The crank is shown as having a worm wheel 30 driv'enjby oscillated by a link 26' extending 'from' a rock' a worm 31 which rotates with a second worm wheel 32 driven by a second worm 33 connected with a pulley 34 driven by power belt 35.

According to the present invention the ash pocket 18 has its refractory walls constructed to deliver air under forced draft, into the refuse in the pocket. In the illustrated embodiment this refers to the bridge wall and the side walls, which at their lower portions are provided with-refractory linings 36 constructed to discharge air into the pocket. Preferably such lining is constructed by building it up of perforated blocks 37, analogous for example to those shown in my prior Patent 1,400,036, patented December 13, 1921. 1

The perforated wall blocks 37 are shown on an enlarged scale in Figure 2 in which it will be seen that the apertures 38 are tapered to give more forcible jets of air and better netration into the mass of refuse in the pocket. At their faces the blocks are shown formed with shallow channels into which the apertures discharge and which tend to protect the apertures from clogging. The rear wall 11, and the non-clinkering or apertured refractory blocks 37 thereof, are inclined inwardly, as stated, as clearly appears by the decided incline of the wall inner line in Fig. 1. .This is a substantial improvement over a vertical wall by reason of minimizing clinker difiiculties, including the tendency of clinkers to bridge across from the rear to the front side of the ocket.

By provided force draft through the apertures 38 the ash pocket is protected and other advantages before enumerated are attained. The passage of the air through the blocks keeps the refractory walls relatively cool, thus preventing the deterioration resulting from overheating. Also the formation of clinkers within the pocket is prevented and the attachment of clinkers to each other minimized as well as the attachment of clinkers to the walls, which is a particularly harmful defect in this typeof furnace. The forcing of air'into the body of refuse tends to complete the combustion of any fuel remaining therein, thus giving greater efliciency from the fuel. By the cor. ling of the clinkers they are in better condition to be crushed and discharged into the ash pit.

I have found that the differences in conditions at different depths in the ash pocket require pressure control and this I have provided as follows. The delivery of air into the pocket is shown divided into upper and lower zones, each comprising two tiers of perforated blocks. The division is made by means of separating refractory tiles '40, dividing the air spaces back of the blocksinto an upper wall passage 41 and a lower wall passage 42, the tile 40 also extending into the outer wall ortion and serving as a bonding element. eparate upper and lower air entrances 43 and 44 are shown for the passages 41 and 42, and upper and lower dampers 45' and 46 control the inflow into each pressure zone. A conduit 47 is shown conducting air to the rear side of the bridge wall from a forced draft air supply 48.

By manipulating the dampers the air pressure and penetration at different levels can be regulated. Thus the lower damper may be opened wider than the upper so as to give more air and penetration into the lower' part of the refuse within the pocket. This regulation enhances the advantages before referred to, giving more complete combustion and better control of clinker difiiculties.

It will thus be seen that I have described a furnace embodying the principles and attaining the objects of the present invention. Since many matters of combination, arrangement, instruction and detail may be variously modified without departing from the principles involved, it is not intended to limit the invention to such matters except in so far as specified in the appended claims.

What is claimed is:

1. In a furnace the combination of a progressive feed grate, a furnace rear wall and lateral Walls bounding three sides of a. refuse pocket or chute of substantial depth, said grate being arranged to give support to the progressing fuel bed as far as the upper front edge of said pocket, a wall bounding the front side of such ocket constituting an' extension of said fue supporting grate but so steep as to give negligible support to the weight of the refuse in the pocket, mechanical means at the bottom of the pocket giving regulated refuse discharge without dumping or emptying the pocket, said rear Wall where it bounds the pocket being inwardly inclined so as to overhang the pocket and prevent bridging of clinkers, and said rear and side walls composed of argillaceous refractory material having air admission apertures substantially throughout the depth of the pocket, and means supplying forced draft to said apertures whereby air is directed into the refuse in said'pocket.

2. In a furnace the combination of a progressive feed grate, a furnace rear wall and lateral walls bounding three sides of a refuse pocket or chute of substantial depth, said grate being arranged to give support to the progressing fuel bed as far as the upper front edge of said pocket, a wall bounding the front side of such pocket constituting an extension of said fuelsupporting grate but so steep as to-give negligible support to the weight ofthe refuse, mechanical means at the bottom of the pocket giving regulated refuse discharge without dum Jing or emptying the pocket, said rear wali bounding the pocket, consisting of superposed tiers of argillaceous refractory blocks so arranged that said wall is inclined to overhang the pocket and produce a substantially non-tapering pocket formation at the lower part of the pocket, said blocks having air admission apertures substantially throughout the depth of the pocket, and means supplying forced draft to said apertures whereby air is direct- Bd into the refuse bed in said pocket.

3. In a furnace the combination of a progressive' feed grate, a furnace rear wall and lateral walls bounding three sides of a refuse pocket of substantial depth, said grate being arranged to give support to the progressing fuel bed as far as the upper front edge of said pocket,- a wall bounding the frontside of such pocket constituting an extension of said fuel supporting grate but so steep as to give negligible support to the weight of the refuse, mechanical means at the bottom-of the pocket giving progressive refuse discharge without dumping, said rear wall bounding the pocket consisting of argillaceous refractory blocks so arranged that said wall is inclined to overhang the'pocket and produce a substantially non-tapering pocket formation at the lower part of the pocket, saidrear wall having air admission apertures at various depths in the pocket, and means supplying forced draft to said apertures, whereby sliir is directed into the refuse bed in said p In testimony whereof, I have afiixed my signature thereto.

WARREN o. DRAKE. 

